MEDICAL PARASITOLOGY

1. MEDICAL PARASITOLOGY Laboratory diagnosis Of parasitic diseases By S.S Eghbali ApCp BPUMS 2008

2. Definitions Medical parasitology: the study of the parasites of man and their medical consequences. Parasite: living organism requiring intimate prolonged contact with another living organism to meet some of its basic nutritional needs. In a more restricted definition, it refers to organisms that are not viruses, bacteria, fungi, rickettsia, or chlamydia and obviously include organisms of varying complexity from a unicellular protozoa to a complex multicellular helminths.

3. Host: organism harboring a parasite. Definitive host: animal harboring the adult or sexually mature stage of the parasite. Intermediate host: animal in which development occurs but in which adulthood is not reached. Life cycle: for survival and reproduction reasons many parasites evolve through a number of morphologic stages and several environments or different hosts. The sequence of morphologic and environmental stages is referred to as the life cycle. Parasitic infection: invasion by endoparasites (protozoa and helminths).

4. Parasitic disease: invasion and pathology produced by endoparasites. Parasitic infestation: external parasitism by ectoparasites (arthropods). Commensalisms: the association of two different species or organism in which one is benefited and the other is neither benefited nor harmed. (e.g. non pathogenic intestinal protozoa) Reservoir host: an animal that harbors a species of parasite that can be transmitted to and infect man.

5. Vector: an arthropod or other living carrier that transports a pathogenic organism from an infected to a non-infected host. Carrier: a host that harbors a parasite but exhibits no clinical signs or symptoms. Zoonosis: a disease involving a parasite for which the normal host is an animal, and wherein man can also be infected. Protozoa: a subkingdom consisting of unicellular eukaryotic (Greek-karyon=nut=nucleus) animals.

6. Vector: an arthropod or other living carrier that transports a pathogenic organism from an infected to a non-infected host. Carrier: a host that harbors a parasite but exhibits no clinical signs or symptoms. Zoonosis: a disease involving a parasite for which the normal host is an animal, and wherein man can also be infected. Protozoa: a subkingdom consisting of unicellular eukaryotic (Greek-karyon=nut=nucleus) animals.

7. INFORMATION EMPHASIS Agent ID and general importance Epidemiology (transmission, distribution, etc) Agent damage capability Diagnostics Control

8. Epidemiology • Although parasitic infections occur globally, the majority occur in tropical regions, where there is poverty, poor sanitation and personal hygiene • Often entire communities may be infected with multiple, different organisms which remain untreated because treatment is neither accessible nor affordable • Effective prevention and control requires "mass intervention strategies” and intense community education. Examples include: • General improved sanitation: pit latrines, fresh water wells, piped water • Vector control: insecticide impregnated bed nets, spraying of houses with residual insecticides, drainage, landfill • Mass screening and drug administration programmes which may need to be repeated at regular intervals

9. The burden of some major parasitic infections

10. Parasitology - protozoology (protozoa), helmintology(worms), enthomology(insects) • Laboratory diagnosis: - life cycle of parasits, material v laboratory diag. • Protozoa – intestinal, genital, urinary, blood, tissue • Worms - Helmints: Nematodes, Cestodes,Trematodes • Ectoparasits: louse, ticks, flies – important as vectors

11. Life cycle of parasits -terminology • Complex life cycle – key to diagnosis • Host – hosts • Definitive host – parasit finishes the growing cycle and is becoming adult in it • Not typical host - parasit cannot develop in it • Transient host – larves are developing in it and not sexual multiplication is performed • Helmints : egg - larvae - adult worm Protozoa :trophozoite - motile cysts – non motile - sexual multiplication - zygota - asexual- schizonts, sporogons

12. Diagnosis • Problematic, not ususals outside endematic areas • Nonspecific clinical manifestation • eosinophilia in helmintoses – not constant sign • Importance of history – personal, travellers, social, economic, food, therapy • Conditions for successful dg: - think on parasitosis - také a good sample – right sample, with good method at right time, send it in appropriate conditions to the lab that is able to identify the parasite, good interpretation: - Knowledge of life cycle is principal

13. Laboratory diagnosis • Usually based on morphology (microscopic) • Demonstration of the parasit in different stages of life cycle in clinical material • Macroscopic examination of the sample (stool or tissue) • Microscopic examination – native smear, staining, concentration method • Serology – detection of antibodies, detection of antigénes • Genetic probes - detection, identification • Cultivation • Animal model

14. Stool for parasitological examination • Macroscopy – blood, mucous, adult worms • Microscopy - native smear - iodine – motility, eggs of helmints, cysts of protozoa, Rbc,Wbc • Concentration methods – separation of cysts of protozoa and eggs of helmints from other material in the stool • Staining - identification – smear of native stool + hematoxylin eosin, trichrome

15. Other material acc.to clinical manifestation • Perianal - Enterobius vermicularis • Sigmoidoscopy - Entamoeba histolytica • Duodenal aspiration - Giardia lamblia • Biopsy of abscess of liver - Entameba histolytica • Sputum - Ascaris lumbricoides, Strongyloides, • Urine - Schistosoma Hematobium • Urogenital sample - Trichomonas • Blood - (malaria, trypanosomiasis, leishmaniosis, filariosis) smear, thick drop - staining Giemsa, H&E, • Serum (Hydatid cyst)

16. Protozoa • Amoeba - Entamoeba histolytica, Entamoeba coli, Naegleria fowleri, Acanthamoeba, Endolimax nana • Flagelata - Giardia lamblia, Trichomonas vaginalis,Leishmania, Trypanosoma • Ciliata - Balantidium coli • Coccidia a Sporosoa - Cryptosporidium, Blastocystis, Microsporidia, Plasmodia, Babesia,, Toxoplasma

17. Nematodes -worms • Enterobius vermicularis, Ascaris lumbricoides, Toxocara canis,cati, Trichuris trichiura, Ancylostoma duodenale, Strongyloides stercoralis, Trichinella spiralis, Wuchereria bancrofti, Dracunculus medinensis • Nonsegmented body, adult worms living in the GIT-e, - diagnosisa: identification of eggs in the stool (morphology of eggs) • Filariae – tin worms parasiting in eye, skin, tissue, transmitted by insects. Larval form- microfilariae penetrate to blood and are transmitted by suckling insect

18. Cestodes - • Head - scolex, segmented body • Hermafrodit, male and female organs are present in every segment - dif.dg. They have not GIT, absorbtion of food. Complex life cycle with transient host (sometimes - human – larval stage of cysticerkósis, echinococcosis) • Taenia solium, Taenia saginata, Diphylobotrium latum, Echinococcus granulosus, Hymenolepsis nana

19. Trematodes - • Usually hermafrodits (ex Schistosoma) • Need transient host • Fasciolopsis, Clonorchis, Paragonimus, Schistosoma

20. Enterobius vermicularis • Definitive host - human • transient - none • dg. – perianal sample – microscopy of eggs • fecal oral transmission - autoinfection

21. Enterobius vermicularis

22. Ascaris lumbricoides • Definitive host: human • Larva migrans: intestin, colon - muc.membrane - blood- lung - cough - mouth - colon • dg. Egg in stool • Infection via contaminated food • Symptoms acc.to localisation of the larva

23. Ascaris lumbricoides

24. Toxocara canis, cati • Definitive host dog, cat • Transient host: rat • Human incidental: human (larves) • dg. serology • transmission: hand food

25. Taenia saginata • Definitive: human • transient: cattle • dg. Segments in stool • Transmission cysticercus in beef

26. Taenia solium • Definitive: pig • transient: rat • incidental: human in small intestin • dg. Serology,body Rare • Contaminated food

28. Echinococcus granulosus • definitive: dog • transient:sheep • incidental: human • Diagnosis: serology,Direct methods • transmission: cyste in meat • infection: mechanic pressure from expanded cyst, prolonged growing, rupture of the cyst and dissemination

29. Echinococcus granulosus

30. Entamoeba histolytica • definitive: human • Diagnosis:trophozoites in stool, serology • dysenteria – diarhea with blood

31. Entamoeba histolytica

33. Naegleria fowleri, Acantamoeba,Balamuthia • Free Living in water • Human (via nose) • Diagnosis:microscopy in CSF- identification of invasive strains Diseases:Negleriafowleri:P.A.M Balamuthia:G.A.E,Acantamoeba:Keratitis

36. Toxoplasma gondii • Definitive: cat • transient: rat • incidental: human • Diagnosis: serology , IgA, IgG, IgM • transmission: food borne, hand, annimal • disease: - intrauterine primoinfection - generalized lymphadenopathy, encystation in organs – abortion, eye……..

38. Trichomonas vaginalis • Definitive: human • transient: none • dg. Cultivation - microscopy trophozoite - from vagina, urine • Sexual transmission • Therapy of both (all) partners

40. Giardia lamblia • definitive: human – small intestin,dog, cat • transient: non • Diag:microscopy – cysts and trophozoits in stool, transient in duodenal secretion • Transmission contaminated food • malabsorption

41. Giardia lamblia

42. Trypanosoma gambiensis (spavá choroba) • Definitive host: insect - fly tse tse • transient: human, monkey • dg.microscopy – thick drop • Transmission bite • Disease – sleeping disease, myalgia, arthralgia, lymphadenopathy, hyperactivity in acute phase, lethargy, meningoencephalitis, coma

44. Plasmodium-malariae, falciparum • Definitive host:Anopheles • Transient host: human, monkey • Diag:microscopy thick drop • Transmission insect bite • disease: malaria acc.to the rate of schizogonia- clinically as fever attacks - tercianna, quartana,

48. PUV CONTROL OF PARASITIC DISEASES A CHALLENGE FOR OUR FUTURE

49. DPUV COMPLEXITY OF PARASITIC DISEASES AND PROBLEMS • The complexity of zoonotic infectious diseases offers, however, several problems which must be solved: • Although the general knowledge on the disease epidemiology and transmission is usually available, the knowledge on local epidemiology and transmission characteristics is still lacking in many cases • Multisdisciplinary approaches and transprofessional team networks are needed for both research and training. Efforts will be needed to convince different ministries and health responsibles to co-work and related political-strategic difficulties must be solved • Funding agencies shall be convinced about the need for increasing efforts at animal level • Studies on geographical distribution and epidemiology of zoonoses by using modern tools are crucial to establish the appropriate local control measures • Field work shall again be encouraged • The need for “old-fashioned” disciplines as Medical Malacology and Entomology shall be emphasized

50. DPUV • THE NEED TO AGAIN EMPHASIZE THE IMPORTANCE OF FIELD STUDIES • Experimental work has sense if it is for the understanding of what happens outside • During years and years we have been developping numerous new, modern, sophisticated molecular tools for the diagnosis of many infectious diseases; once the new test obtained, a field trial has been usually performed to verify its usefulness; and afterwards, only a few or nobody is applying it in endemic areas • Too sophisticated to be applied in many developing countries • Too expensive and consequently unaffordable • Too much similar tests for the same disease, so that health responsibles become lost